Automatic common-battery telephone system.



ET D. FALES.

AUTOMATIC COMMUN BATTERY TELEHONE SYSTEM.

APPLICATIN HLED NOV. 5 T906- RENEWED SEPT, 19| '91T- 1,268,069. PatentedMay 28, 1918.

2 SHEETSWSHEET 2. 7.-

/dgg

UNITED STATES PATENT OFFICE.

EDWARD D. FALEB, O CHICAGO, ILLINOIS, ASSIGNOB, BY MESNE ASSIGNMENTS, TO

AUTOHAT ELECTRIC COMPANY, A CORPORATION 0F ILLINOIS.

AUTOMATIC COMMON-BATTERY TELEPHONE SYSTEM.

Speolnoation of Lettere ratent.

Patented May 28, 1918.

Application tiled November 6, 190B, Serial No. 342.959. RenewedSeptember 19. 1917. Serial No. 191831311.

To all whom. it mmf emma-rn.'

Bc it. known t iat I, Row/inn D. FALns, o citizen of the United Statesof America, and resident. of Chicago, (look county Illinois, haveinvented a certain new and useful Improvement in AutomaticCommonllatterv '.lolephone Systems, of which thc following` is aspecification.

My invention contemplates an improve.- ment on the common batterytelephone system disclosed in mv prior application Serial No. 336,353,tiled September 26, 1006,

'lhe ohjeet of my present'l invention is to `provide certain features ofimprovement, t et nils ot construction. eomhimitions ot" elements andcircuit. arrangements tending` to improve the general etlieiency of anantomatie eonnnon battery teleihone exchange system, as well as to stillnrther improve and simplil'y the connectors thereof.

To the tmegoinglr and other useful ends` my invention consists inmatters hereinafter desorihed and claimed.

la the aeeompanyiiu;` drawings. Figure 1 is a diagrannnatic perspectiveview of one eniiaaliment of my improved connector.

Fig. 2 shows diagrammatieally a calling and a ealled substation(-.onneeted hy means ot a central olliee equipment., in a systemembodying the prinei )les of my invention.

in the said otliee tie. calling lsubstation .#500 has allotted to it thefirst-seleetor (l ol' the. general type disclosed in United StatesPatent No. t-tll. issued March lll` ltltlt. to Keith` liriehson &liriekson. it will he seen that the eentral battery ll has its`osit-.ivo terminal preferably grounded at (i. The operating relaysare.. as hereinafter e.\plained` normally eonnerted to the non-froumledterminal ol' the said hattery` so that the suhseriher hy grounding hisline emulnetor may operatethe said switches. as is usually the custom insystems ol'4 this class. ln addition to the said lirstseleetor (l there.is shown mv im roved eonneet-.or switch 'D and another lrst-seleetor (1'allotted to the ealled lino. Also. at ifi is `shown n lalsy-signalin fmachine. and at. l" a ringer generator is s town. Suhstation #500 isshown as having operated the eentral otliee switches and establishedeoinieetion with the substation #120. which is shown in its normalposition. 'Ihe substation A may be of any suitable or approved type.rPhe one. in eonneetion with which I have elected to illust-.rate myinvent-ion is an improvement. on the substation disclosed 1n UnitedStates Patent No. Llulh r rranted .Tune 30, itil-t, to Keith` Ericksonand Erickson, and comprises a receiver t3, a switch-hook for controllingthe suhstat ion circuits., which eonturollini.'` operations areaccomplished through the medium of an suitable lneans` sueh as the eamarms 5, and 6. The said snhstat ion eomprises the usual transmitter 'i'.indnetioncoil 8 having the primary winding.r tl and secondarywindinplt). the ringer ll` and condenser 12 in the ringer eirenit.Heine; an automatic substation it is provided with thc usual verticaland rotary impulse springs 13 and l-t and the release springs 15, 16 and17, Said solist-ation is. of course` provided with a dial which is notshown hut. which is secured to the shaft. 18. together with the lockingdog;` 19. Fiirthermom, there is a locking;` cam 20 that loeks the dop`19, while the receiver is on the s\vitelihook` to prevent. a rotation ofthe dial. 'l`he suhstation ground circuit. is normally broken betweenthe ground springs .ll and 3:2 hy the cani arm t; lint when said springsare permitted to engage. laronnd eonneetion is provided to the groundpost' :ttl and to the release sprin r i7'. as is well known intelephones ot this type. ltor o nratinrir the impulse springs J3 and l-ltie substation is provided with an impulse wheel il secured to the shaft18 that earries on its periphery the so-ealled vert-leal teeth .25 andone rotary impulse tooth 26. 'lhe said impulse teeth are so arrangedthat. when the dial is drawn down the impulse springs 14 nml 13 arc notcarried into eontaet with the ground est. 23; hut as the dial returnsthe vertical teeth engaeo the vertieal impulso spring: 13. and a terthey have eompiet-ed their work the rotary impulse. tooth .tl o cratesthe rotary impulse spring: lvl. In t is operation the suhserilnn"srertieal lino conductor .27 is tirst. I,fii'eu n numher of groundimpulses alnl then the rotary line eondnctor 28 is iven one "roundimpulso. lt will lie notieed that. as lian: as the dial is out ol`normal position the eonstruetion is snrh that the dog lll permits theprimary circuit sprin 29 and 30 to separate, thus preventing t eimpulses that are delivered to either line conductor from passin to theother. The rin g device of su station A comprises a pus button 31secured to the spring 32. In addition the springs 33 and 34 are soadjusted that when t e button 31 is pressed the springs 33 and 34 engagebefore the springs 32 and 33 disengage. Furthermore, it will be observedthat when the button 81 is pressed and the springs 33 and 34 engage, therotary line conductor 28 is then grounded instead of the vertical lineconductor. Furthermore; the selector C and the selector C are identicaland are of the general t pe disclosed in the reviousl mentioned atentNo. 815,321. he only iiference between the selector C and the selectordisclosed in said patent is that the selector C has two springs inseries with the release relay and private wiper. These springs are socontrolled Vby the release magnet that when the latter becomes energizedits. armature operates to disengage the said springs, therebydisconnecting the release rela from the private wiper. The object of tis provision will be explained in connection with the release of thecentral oiiice switches. In the drawing both selectors are similarlyrepresented. he line wipers and 36 and the private wiper 37, which arecarried by the switch-shaft,-arc shown; also the side switch wipers 38,392 40 and 41. In normal position the said wipers engage the contactpoints 42, 43, 44 and 45; 1n second position the contacts 46, 47, 48 and49; and in third position the contact points 50 51, 52 and 53. Theoperations of the switch while a call is being made are, of course,controlled b the vertical and rotary line relays 54 an 55, which in turncontrol the vertical magnet 56, private magnet 57, rotary magnet 58 andrelease magnet 59. After the side switch passes to third position therelease of the selector, as is well known, is controlled through theso-called back-release relayl 60. As soon as the switch 'is operated theswitch-shaft permits the oil-normal springs 61 and 62 to come intocontact, whereby a arding potential is established by way o the privatenormal conductor 63 to the private bank contacts of the connectors toprevent another subscriber from interferin with the line establishingconnection wit the said line by way of the normal line conductors 64 and65. When the oil-normal spring 61 is in normal osition, however, itrests in engagement with the spring 66, whereby the brdge-cut-ofl' relay67 is retained in connection with the private normal conductor 63, sothat whenever the line is called the said bridge-cut-oif relay 67 isenerized, whereby the line relays 54 and 55 are 66 isconnected from thebattery and from The general mechanical details are very much the same,althou h the circuits are materially different. he usual switchshaft 68of said connector is provided with the line wi ers 69 and 70 and theprivate wiper 71 w ich have allotted to their use the line and privatebanks 72 and 73. Said shaft is alsoY provided with the cam 74, lon'tudinal teeth 75, circular teeth 76, norma post arm 77 and coil sprin78. Said connector-switch is also provide with verso tical and rotaryline relays 79 and 80 and the vertical and rotary magnets 81 and 82 andrelease magnet 83, rivate magnet 84, ringer relay 85, and the ack-bridgecoil 86 which is composed of the windings 87 and 35 88. The side switchH performs the usual functions through the medium of the side switchWipers 89, 90, 91, 92 and 93. The operation of the system ma be moreclearly understood if each step uring a call is followed up in detail,as in the following:

It will be assumed that the subscriber at substation A wishes to callthe subscriber at A', the number of which latter it will be assumed is120. When the receiver 2 is 95 removed from the switch-hook 3 the camarm 5, upon leaving the spring 94 which it normall engages, permits thes ring 94 to leave t e spring 95, thus brea ing the ringer circuit, andthe same operation ermits the primary circuit springs 29 an 30 to comeinto contact. The first digit bein 1 the subscriber operates his dialaccor ingly, and as soon as the dial is drawn down the ground s rings 21and 22 come into 105 contact, estab ishing a ground connection from thesubstation round G' to the ground post 23. As t e dial returns, the

1m ulse wheel 24 thrusts the vertical impu se sprin 13 against theground post 23 110 once, and t en thetrotary im ulse tooth 26 in asimilar mannercarries t e rotary impulse s rin 14 onto the ground post23 once. he e conductors 27 and 28 are, therefore,`each grounded once,and as a result the vertica 4line relay 54 of the selector C is firstenergized by a flow of current from the substation ground G through theground springs 21 and 22, to the vertical impulse s ring 13, thence tothe vertical line con uctor 27, side switch wiper 38, contact point 42,vertical line relay 54, bridge-cut-o relay springs 97 and 96 to thebattery lead'98, and through battery B Vto ground G. The vertical linerelay 54, upon ener izing, presses the line relay springs 99 an 100 intocontact, thus energizing the vertical magnet 56 once by a i How ofcurrent from ground G2 through the springs 99 and 100, private springs101 and 130 102 to the vertical magnet 56, thence to the battery lead98, and from battexy B to lrround (i. The vertieallnagnet t5 thereore,operates to raise the shaft wi ers 35, 36 and 37 to the first level, ina wel -known manner. This operation having been aeeomplished, then whenthe rotary line conductor 28 is rounded the rotary lino relay on isenergize and this in turn operates the privato ina net 5T, which latterthen tri s the side switch to second osition, estrablis iing anenergizing circuit tirongh the rotary magnet 58 for rotating the wipersonto sonne trunk line. The energizing circuit through the said rotaryline rela 55 extends `from the substation ground i to the ground post28, thence to the rotary impulse sprin 4, rotary lino conductor 28, sidoswitc i wi er 39, contact point d3, rotary line relay 55, rid e-cut-olrelay s wings 103, tl'i' and 96 to the iattery lead 98 tiience throughhattery ll to ground (i. 'i`he said rotary lino relay upon pressing thespring lll-t onto the spring 99 closes an energizing circuit through theprivate ma net 5T, as aiready stated, from ground (1 through tho springstitl and 10i to the said )rivale magnet: 5i. thence to the battery cad98 and through battery B to ground (l. The private magnet upon operatingpermits the sido switch to pass to second position, at. which time theside switch wiper l0 engages the grounded contact point i8, whereby theeuergizing circuit for the rotary magnet 58 is closed lroin ground (iito the contact point iH. side switch wiper it), interruptor springs |05.rotary ma net 5S to the battery lead 9S. thence througi battery B toground (l. 'lhe rot-ary magnet is then energized. and the wipers 3?.:ttt and 3T are carried into engagement with the lrst trunk. lt the saidtrunk is not iulsy. the armature ol' the rotary muguet 5H. as is wellknown. hy nicchanieally operating the armut-ure of the private magnet5T, releases the side switch to third position: hut il' the said trunkis husy the privato magnet'. energizes at the same time thatI theprivate armature is depressed and at. the instant that the privato wiper37 engages the grounded contact'. so that the .side .switch is held insecond position and un energizing circuit is maintained through therotary magnet 58 until the private wiper 37 is carried onto the terminalol' au idle trunk and tho energizing circuit'l |`or the private magnetdestroyed. .'\l the suino `instant the side switch. of course. passes tothird position and the wiper itl leaves the contact; point i8. thusbreaking the energizing circuit l'or the rotary magnet .GH and bringingthe selector to a stand- Istill. 'lho passage of the sido switch tothird iosition carries the side switch wi ers :its an :itl onto thecontact points 5t) antltil. and the line cominci-ors 27 and .28 areplaced in connection with the line wipers B5 and 30 whieln'havingalready entered into connection with the trunk conductors 106 and 107that lead to the connector l), place the said conductors 27 and 28 inconnection with the said connector l). The passage of the side switch tothird ostion, furthermore, establishes a guar in potential at theprivate wiper ti'i' when t lo side switch wiper -tl engages the groundedcontact point 53. 'This guarding potential arrives at, the said privatewiper 3T from the ground (l to the contact point titi, through the wiperYtl bach-release relay titi, s wings 16:2 and 16: to the private wiper37, tuts protecting tho trunk conductors 106 and 10i from heilig seizedfor the time being. The line conductors 9T and 28 having been thusextended to the conductor D the succeeding impulses from the substationA are directed to said connector D. The second digit being 2 thesubscriber operates his dial accordingly, groundingr the verticali lineconductor 2T twice and the rotary line conductor 2S once, as ulread'explained. llach time that the vertical lino conductor is grounded theverl ical line relay Tt) of the connector l) is euergizcd by n low ofcurrent from the sulistation "round G' to the vertical line conductor2i', tronco through the selector side switch wiper 33 to the contactpoint 50, vert ical line wiper 35, vertical trunk conductor 10G to thevertical line relay 79, thence through said relay and through the sideswitch s winer Utl contact point 10S to the hatt-cry lead tibi, and frombattery l5 to ground G. 'lho vertical line relay 75h eac-h time that itattracts its arnniture. lorces the line relay springs ltlt) and il()into contact. sending an impulso each time through the vertical magnetril l'rorn ground ti through the said springs tuti und llt), conductorill (Fig. l). privato springs ll. and liti. conductor il-l` sido switchwiper liti. contact point; lili to tho vertical magnet Si, thence tobatter lead HH, and through haltery li to ground (i. .\s disclosed inthe aforesaid patent the vertical magnet when energized operates toraise the swilcleshull und wipers. 'l`he vertical mugnet Hi heing ener*ized twicethe wipers (it), T0 und Tl are raised` to the second level.'.lho ground im misc to the rotary line conductor :23. after t leswitch-shaft 11H has thus heen raised. energizes the rot ary linz` relaySti of the connector. which in turn operates to euergize the privatomuguet Hi. 'lhe circuit over which the .said rotary line relay Ht) isenergized extends from the suits-lation ground tl to thc rotary lineconductor 2s, thence to the side switch wiper :iti of the selector t.contact point hl, rotary line wiper titi. rotary trunt conductor itl? totho said rotary liuc relay Sti, thence, to hatten-y lend tti. undthrough liattery li to ground (i. 'llu` rotary line rc ay Htl. uponattracting its armature, forces the ring 116 onto the spring 109, whereba ow. of battery current is sent throug the private magnet 84 fromground G", through the springs 109 and 116, conductor 117 to the privatemagnet 84, thence throu h conductor 118 to the side switch spring 9contact point 108 to the battery lead 98, thence through battery B toground G. The private ma et 84, upon attracting its armature and t endenergizing, operates, of course, to release the side switch H fromfirst to second posltion. The effect of the shifting of the side switchis to substitute the rotary magnet 82 for the vertical magnet 81,bringing the former under the control of the vertical line relay 79 whenthe side switch wiper 92 leaves the contact point 115 and engages thecontact point 119. The side switch is so constructed that the wiper 93engages the contact point 108 when the side switch H is in Iirst andsecond poistions. The contact point 108 is connected with the batterylead 98 and the contact point 120 is connected with the private wiper 37and, consequently, with ground, when the connector is engaged. With aside switch wiper such as 92 there is a possibility that the wiper mightoverlap the contact points 108 and 120. Accordingly, to meet thispossibility, the wiper 93 is twisted, as shown, and the contact made bythe said wiper with the said contact points, instead of being a slidingcontact as is the case with the wiper 92, is like the make-and-breakcontact between the ordinary relay contact springs. The third digitbeing 0, when the vertical line conductor 27 is grounded ten timescorresponding to the digit 0, upon the operation of the dial thevertical line relay 79 then energizes ten times over circuits that arenow known. Said relay 7 9 in turn causes the energization of the rotarymagnet 82 step-by-step. The energizin circuit through said rotary magnetextends from ground G through the line relay springs 109 and 110,conductor 111, private springs 112 and 113, conductor 114, side switchwiper 92, contact point 119 to the rotar magnet 82, thence throughbattery lea 98, and through battery B to ground G. The rotary magnet 82bein energized ten times the shaft 68 is rotate ten steps, in a mannerdisclosed in said patent, whereby the wipers 69, and 71 are carried intoengagement with the tenth terminal of the second level, from whichterminal lead the normal conductors 123, 124 and 125 that extend to theselector C of the called line, the former two of which conductorscontinue through to the called substation #120. After the connector hasthus been operated the ground impulse to the rotary line conductor 28energlzes the rotary line relay 8O of the connector over circuits thatare already `well known, which relay in turn oplerates the privatemagnet 84 as bef fore. he said private magnet upon energizin if the lineis busy, will close a circuit t rough the release magnet 83 that willrelease the switch; but it will be assumed for the present that the lineis not busy and that the side switch H passes to third position when theprivate magnet 84 deener 'zes As soon as the side switch passes to tiirdosition a guarding potential is cstablishe at the private wiper 71, whenthe side switch wiper 91| en ages the grounded contact point 126. T isguarding potential prevents any other subscriber fromca ling in onthe-line #120 for the time being. This guarding potential, furthermore,sends a flow of current through the bridge-cut-o' relay 127 oi. theselector C for energizing said cut-oli' relay from the private wiper 71to the private normal 125, thence through the switchshaft springs 128and 129 to the bridge-cutoff relay 127, thence to the batter lead 98,and through battery B to oun G. The said relay 127 upon energizingseparates the springs 130, 131 and 132, disconnecting the line relays133 and 134 from the battery lead 98 and from each other. The sideswitch wiper 93 upon passing to third position engages the point 120,which changes the polarity of the conductor 135 from batter to ground,thereby completing a circuit w ich givcs battery current to` theAcalling subscriber for talking `purposes. This circuit extends fromgroun G* at the selector C, through the side switch wiper 41,back-release relay 60, springs 162 and 163 to the first-selector sha twiper 37, conductor 136, contact point 120, side switch wiper 93,conductor 135, vertical line relay 79, trunk conductor 106, shaft wiper35, contact point 50, side switch wiper 38, vertical line conductor 27,springs 30 and 29 to the springs 32 and 33, transmitter 7, primarywindin 9 of the induction-coil 8, rotary line con uctor 28, side switchwiper 39 and contact point 51, shaft wiper 36, trunk conductor 107,through the rotary line relay to the battery lead 98, thence throughbattery B and to ground G. This talking battery current in passingthrough the line relays 79 and 80 energizes said relays. The said relays79 and 80 upon energizing operate to close in contact the springs 109,110 and 116, and the springsv 137 and 138, and to disengage the springs138 and 139. When the springs 109 and 110 engage an energizing circuitis closed through the ringer relay extending from ground G through thesprings 109 and 110, conductor 111, private magnet springs 112 and 113,conductor 114, side switch wiper 92, contact point 146, conductor 147,through the ringer relay 85 to the battery lead 98, thence throughbattery B and to ground G. The ringer relay upon energizing shifts thesprings 165 and 164, through the release magnet 59 to the battery lead98, thence through battery B and to ground G. 'lhe release magnet 59upon energizing attracts its armature, which discngages the springs 162and 163, thus breaking the energizing circuit; through the release relay60 and the release magnet 83, whereby the armature 166 resumes itsnormal position and releases the connector. The release relay 60 alsodeenergizes and the springs 164 and 165 disengage, thus destroying theenergizing c ircuit through the release magnet 59 which now operates ina Wellknown manner to restore the first-selector C. It will beunderstood that the release mechanism of the connector, comprising therelease magnet 83, release armature 166, release link 140', double dog158, is the same as that disclosed in the selector patent cited-that is,when the release armature 166 is attracted the link 140 latches thedouble dog 158, and when the release magnet 83 denergizes, the doubledog 158 is then withdrawn from the shaft 68, which latter falls tonormal position, and the said double dog at the same time restores theside switch H to normal or first position through the medium of thedouble do releasin arm 159, as is well known. Wlen the re ease magnet 83andthe backrelease rela 60 of the selector C energize in series, asescribed, the release ymagnet 59 of said selector C attracts itsarmature, which latter is provided with the springs 162 and 163 whichare adapted to separate when the armature of the release magnet isattracted, as explained. It Will be evident that when the release magnet59 ener gizes it causes a denergization of the connector release magnet83 producing the release of said connector, and at the same time thedenergization of the release relay 60. The latter then permits thedeenergization of the release magnet 59, which magnetat once drives theselector side switch to first position, permanently destroying thetrunk-release circuit by removing the side switch wiper 41 from thegrounded contact 53, and there also follows a release of the selectorswitch-shaft, which breaks the connection between the selector C andconnector D. As is Well known, busy lines are protected by guarding[potentials and if the called line appens to e bus when the privatemagnet 84 is energized or the last time, as already explained, theconnector switch D will be released at the instant that the privatesprings 167 and 168 are brought into contact, since the private Wiper 71is then in engagement with the grounded contact. The release circuitextends from the grounded contact to the private wiper 71, thence to theside switch wiper 91, contact oint 169, private springs 167 and 168,reease magnet 83, conductor 177, side switch wiper 93, contact point 108to the battery lead 98, thence through battery B and to ground G. Therelease magnet 83 upon en ergizing releases the connector switchshaftand side switch, as is well known, and, of course, the release circuitis broken as soon as the private wiper 71 leaves the grounded contactpoint. The subscriber at the callin substation then, upon prcssin r thesignaling button, receives a busy signal-` ing current from the busymachine E, over the conductor 171, normal sprin fs 172 and 173, ringerrelay springs 174 an 175 to the vertical conductor 176, condenser 160,trunk conductor 106, shaft wiper 35, side switch wiper 38, vertical lineconductor 27,' springs 30 and 29, through the signaling device,transmitter 7, primary winding 9 of the induction-coil 8, rotary lineconductor 28, side Switch wiper 39, switch shaft wiper 36, trunkconductor 107, through the rotary line relay 80 to the battery lead 98and back to the bus signaling machine E. The subscriber wil then hang uphis receiver, grounding both line conductors 27 and 28 and as a resultsimultaneously energizing the line relays 79 and 80 of the connector D,thus bringing the springs 137 and 138 into contact. An energizingcircuit is established through the release magnet of the connector inseries with the release relay of the firstselector C. The energizingcircuit extends from ground G4, as previously traced, to the shaft wiper37, conductor 136, through the trunk-release springs 137 and 138,through the release magnet 83, side switch wiper 93, contact point 108to the battery lead 98, thence through battery B and to ground G. Therelease of the central oiice switches is then brought about, aspreviously explained-that is, the selector C is disconnected from theconnector D and the latter is fully restored; and if the subscribercontinues to retain the release springs 15, 16 and 17 in contact for anextended length of time, then as soon as the selector side switch isdrawn into first position by the dee'nergizaf tion of the selectorrelease magnet the line relays 54 and 55 of the selector energizesimultaneously over circuit that are known, again energizing the releasemagnet 59 by pressing the line relay sprin s 99, 100 and 104 intocontact. Of course, t e engagement of the line relay springs 100 and 104energizes the private magnet 57, which latter connects the releasemagnet 59 with the line relay spring 100, and the enga ement of the linerelay sprin 100 with t e ground spring 99 energizes t e release magnet59, as is Well known. This energizing circuit through the release magnetis, of course, broken when the subscribers release springs 15, 16 and 17separate. From the description of the circuits it will be seen that ifthe called subscriber hangs up his receiver beond motion to connect witha line in a se lect-cd group for extending connectlon to a called line,a grounded source of current, and' means operated by current from saidsource responsive to said device for ap lying signaling current to theselected ca led line, as set forth.

9. In a telephone exchange system, acommon battery connector having`vertical and rotary switching motions and signaling and releasingr andcurrent-feeding operations, .a pair oi' line relays having complete andd1- rect control of all of said operations, and means for switching abattery in series with and between said relays, as set forth.

10. An automatic trunking switch provided with a trunk-release circuit,a release relay in said circuit, a release magnet controlling saidcircuit` a release magnet energizing circuit controlled by said relay,and means for supplying talking current over a portion of saidtrunk-release circuit.

11. In an automatic telephone exchan e system, a selector provided witha trun. release circuit, a release relay in said clrcuit, a releasemagnet provided with normally closed contacts controlling said circuit,a release magnet energizing circuit, said relay provided with normallyopen contacts controlling said energizing clrcuit, and means forsupplying talking current over a portion of said trunk-release circuit.

12. In an automatic telephone exchange system, the combination ofautomatic switches, a talkin circuit, a trunk-release circuit betweenswitches, and means for supplying electric current over a portion ofsaid trunk-release circuit to the talking circuit.

13. A telephone exchange system provided with subscribers lines andrelease trunks, and means for supplying battery current over the releasetrunks to the lines for talking purposes.

14. In a telephone exchange system, the combination of a release trunk,a release circuit, a telephone, a tele hone circuit, and a source ofcurrent, sai circuits including said release trunk and source ofcurrent.

15. In a telephone exchange system provided with subscribers lines andselectors and connectors, whereby talkin circuits are establishedbetween calling an called subscribers, means for supplying battercurrent through selectors and connectors y devices therein not includedin the talkin circuits, and then over said circuits to cling lines andalso to called lines.

16. In an automatic telephone exchange system provided with subscriberslines and automatic connectors means under the con- :nl of the callinsubscribers for supplying talkl current rough the connectors to the caling lines, and release trunks over which the talking current issupplied.

17. In a telephone exchange system, a subscribers telephone, a selectoraprovided with a private wiper, a source of t current and a circuitincluding said telep one and private wiper and source of current inseries.

18. An automatic telephone system comprising a connector provided with arelease magnet, a side switch, a couple of ener 'zing circuits for thesaid release magnet, eac circuit comprising a iirst and second switchpoint, each of said energizing' circuits havmg one of the switch ointsthereof open and the other closed whlle the magnet is deenergized, theopen switch point of the rst of the said energizing circuits beingprovided by a p-air of springs, and the open switch point of the seconof said energizing circuits being provided by a second pair of springs,and means for operating said springs, the closed switch points for thesaid circuits being provided by the springs of the side switch, as setforth.

19. In a telephone system, a trunk line, a trunk-selecting switch forselecting said trunk, a single-wound release relay therefor controlledover said trunk, and means for supplying current through the windin ofsaid relay to the talking circuit for tal 'ng purposes.

20. In a telephone system, a trunk-line consisting of a tpair of talkingconductors and a third con uctor associated therewith, and means forsupplying current over the third conductor to one of the talkingconductors for talking purposes.

21. In a telephone system, a trunk-line consisting of a pair of talkingconductors and a third conductor associated therewith, and meansincluding said third conductor for bridging a common battery between thetalking conductors of the tru -line.

22. In a telephone system, a battery, a telephone line, a connectorcommon to the system, an individual trunking switch for said telephoneline, and means including portions of said individual switchconstituting a battery bridge across the talking circuit at theconnector.

23. In a telephone system, a connector having one motion to select oupsand another motion to find the ca ed 11ne in any selected group, meansincluding an automatic trunk selector for extending a trunk side switchwhereby in its final osition the said current source is connecte tosupply talking current to the calling line.

25. In a telephone system, subscribers lines, means including a finalconnector switch controllable over a calling line for extending aconnection to a called line, a central source of talking currentconnected in bridge of the calling line upon the completion of theconnection and before the called subscriber answers, and a progressivelymovable side switch in said connector for closing said bridge.

26. In a telephone system, subscribers lines, means including a selectorswitch and a connector switch controllable over a calling line forextending a connection to a called line, release magnets in saidswitches, a release relay in said selector controlling the circuit ofits release magnet, an energizing circuit including the said relay andthe release magnet of the connector in series under the sole control ofthe calling subscriber, and means including a relay denergizedresponsive to the opening of the calling line for closing said circuit.

27. In a telephone system, an established connection between a callingand a called line including an automatic connector switch, a relay insaid connector energized over the two sides of the calling line inseries during conversation, a release magnet in said connector, acircuit for said magnet open at a single point under control of saidrelay, and means at the calling substation for opening the line at thetermination of conversation whereby said relay is denergized to closethe circuit of said release magnet.

28. In a telephone system, subscribers lines, means including aconnector switch controllable by separately grounding the two sides of acalling line at the substation for extending connection to a calledline, means for supplying current to the talking bridges at the calllngand called substations, and releasing means in said connector under thesole control of the calling subscriber and operative responsive to theopening of the talking bridge at the calling substation to release theconnection.

29. In a telephone system, means for connecting a calling and a calledline including an automatic connector switch, a relay in said connectorenergized upon the completion of the connection to close the talkingconductors, a second relay energized over the two sides of the callingline in series, a source of signaling current, means at the callingsubstation for denergizing said second relay and circuit connectionswhereby upon the denergization of said second relay the said first relayis denergized to connect said source with the called line.

Signed by me at Chicago, Cook county, Illinois, this 1st day ofNovember, 1906.

EDWARD D. FALES.

Witnesses:

ARTHUR B. Srmr, Hammam* M. MERRIAM.

